1. Field of the Invention
This invention relates generally to the field of prosthetic hand and arm attachments, and more particularly to a multi-function body-powered prosthetic wrist unit that provides over 270° of smooth pronation and supination rotation with a plurality of locking positions, wrist flexion and extension from 0 to 50° with several locking positions, and a quick disconnect connection for attachment of a variety of terminal devices, such as hooks, electric hands, tools, implements, and other specialty terminal devices, thereto.
2. Background Art
Throughout this disclosure the expression “terminal device” is used in the ordinary vernacular of arm prostheses as a device (such as a hook, hand, electric hand, tool or implement) added to the most distal end of an arm prosthesis, for example at a wrist location. In the context of the present wrist unit invention, the terminal device is the device that is attached to the wrist unit. The phrase “active control” refers to motion between adjacent parts that is achieved by body powered harnessing. The phrase “passive control” refers to motion between adjacent parts that is achieved by direct application of external forces.
There have been a large number of prosthetic devices for use by amputees who have lost at least one or both hands, or one or both arms. Many of the devices are body-powered and some are driven, or at least assisted, by electrical, myoelectrical, and/or pneumatic means.
Most extremity prostheses currently in use have a terminal device (such as a hand or hook) controlled either by movements of a shoulder harness transmitted via a cable (i.e. body powered), or by myoelectric control (i.e., motors triggered by the contraction of muscles in the residual limb). However, conventional actively and passively controlled prosthetic devices have only one or two controlled degrees-of-motion, and provide limited ability to grasp, properly position, and manipulate the terminal device.
Thus, there exists a need to provide a prosthetic wrist device having improved control of multiple degrees of pronation and supination rotation, wrist flexion and extension, with a plurality of locking positions, along with a provision for quick and easy attachment of a variety of terminal devices, such as hooks, electric hands, tools, implements, and other specialty terminal devices.
Perez, U.S. Pat. No. 3,490,078 discloses a flexible sleeve for a forearm stump which has a threaded female member at the end of the sleeve into which can be threaded a handle of a tool.
Bengtson, U.S. Pat. No. 3,802,302 discloses a tool holding prosthetic device having a threaded connector devices for attaching various tools and shows the use of a detent ball.
Winter, U.S. Pat. No. 3,942,194 discloses a device for attaching to a hand to which an implement can be removably fastened.
Adkins, U.S. Pat. No. 4,661,113 discloses a device which is attachable to an amputee's prosthesis to enable the amputee to swing a golf club or other device which requires swinging.
Keith, U.S. Pat. No. 4,944,765 discloses an artificial arm prosthetic drive device for holding a rotatable tool.
Norton et al, U.S. Pat. No. 5,163,966 discloses a prosthetic limb having a means for grasping and holding a bar or tubular member.
Farquharson et al, U.S. Pat. No. 5,464,444, commonly owned with the present invention, and hereby incorporated herein by reference, discloses a terminal device that is attachable to the end of a prosthesis on an arm and serves as a universal attachment site for a variety of tools and implements designed to mate with the device.
The present invention is distinguished over the prior art in general, and these patents in particular by a multi-function body-powered prosthetic wrist unit that is attachable to the end of a prosthesis on an arm and provides over 270° of smooth pronation and supination rotation with a plurality of indexed rotation locking positions, wrist flexion and extension from 0 to 50° with three locking positions, and a quick disconnect connection for attachment of a variety of terminal devices thereto. Integral cable release assemblies provide body powered release for pronation and supination rotation and flexion and extension. Cable operated locks can be retracted or released passively by body-powered harnessing, and allow momentary (pull-to-release) or alternating (pull/relax) locking functions.